A települési vízgazdálkodás stratégiai kérdései

Translated title of the contribution: Strategic questions of urban water management

L. Somlyódy, K. Buzás, A. Clement, I. Licskó

Research output: Contribution to journalArticle

Abstract

Presently the objective of urban water management is to deal jointly with water and material budgets, preferably in such a way as to establish closed cycles. The strategic analysis was made for two time horizons: For the period until Hungary joins the EU and for a longer period after that. This study analyses the strategic questions of drinking water supply, collection of waste waters and precipitation waters and the treatment of waste waters. The ratio of the population supplied by piped drinking water reached, by the turn of the millennium, 98%. The total volume of drinking water supplied has been significantly decreasing during the last decade. The fraction of surface waters in this supply was reduced to 5-6%. At national level the magnitudes of available water resources and of the capacities of the waterworks are sufficiently high to meet the expectable future water demands. However, there are already problems with the quality of drinking water, although they do not yet involve those relevant to public health. Concentrations of iron and manganese exceed the limit values of the Hungarian standards at more than 60% of the registered waterworks. This ratio will reach 70%, when we do consider the recent directives of the EU. There will be a need for removing iron and manganese at several hundred waterworks. Concentrations of ammonium ions are higher than the limit values of the relevant EU directive, at more than 60% of the Hungarian subsurface water resources. Organic matter (from which chlorinated hydrocarbons might be derived after chlorination, made for disinfection) is of higher concentration that the limit value of the EU directives, in the subsurface water resources, especially in the area over the River Tisza. Arsenic of natural origin occurs with concentrations much higher than the Hungarian limit value (50 μg/1) in a significant and well definable part of the great plains (Alföld). Compliance with the EU limit value (10 μg/1), will require expensive technological changes at a large number of waterworks. Adoption of EU guidelines might also decrease the use of subsurface waters in respect to boron, as well. A problem of strategic importance might be represented by the non-excludable presence of the protozoa Cryptosporidium in the raw waters of waterworks based on surface water intake. In the lack of the results of appropriate investigations we do not have information on whether the applied disinfection agents are able to remove micro-organisms that are resistant to such agents, or not. In respect to water quality the most unfavourable conditions are found in the Tisza River Valley and in the area beyond the River Tisza.:- there are only very few waterworks, which would meet the EU requirements (Figure 1.). Compliance with the EU requirements, that are stricter than the Hungarian ones, is technically possible, but would need an investment of the order of 100-170 billion HUF. There are no Hungarian legal regulations in conformity with Directive 91/271 of the EU, that would clearly define the necessary level of urban waste water collection systems and treatment plants. Effluent standards are different and so are the categories of sensitivity. The Directive does not, however, defines exactly many items, and thus gives a chance for misinterpretation, that could result in significant expenditures. For example, no technological solutions are specified but only the parameter values to be achieved. The definition of sensitivity could also be the basis of misinterpretation. One could question the need for expensive nitrogen removal in the cases of lakes where the algal growth is limited by phosphorus only. As contrasted to this, nitrogen removal would be very important at drinking water reservoirs, because of the high nitrate levels. Improper interpretation of the term rivers reaching sob-besins might quality the whole territory of Hungary, as a "sensitive" area. Similar is the case with the term "less sensitive" areas: Our rivers of high dilution capacity might all rank into this category, thus allowing (in justifiable cases) the use of cheap mechanical treatment only. The given limit values can also be questioned. Compliance with phosphorus limit value of 0.5 mgP/1, would only be justifiable in the case of sensitive lakes, such as Lake Balaton. An analytical method is shown for various settlement categories, sensitive areas and vulnerable areas. This method estimates the expectable quality of Hungarian rivers for 57 regions, using an aggregated model. The aspects of analysis include: - investment costs (based on the analysis of several waste water treatment procedures); the period of implementation; the level of the services; the rate of changes of emissions (into surface waters, soil and subsurface waters); the impacts on sensitive and vulnerable areas and on the water quality of the rivers (changes in emissions and water quality were analysed for BOD5, NH4-N, NO3-N and TP). The plans were evaluated for four basic levels (to be reached as a final result): (1) "mechanical" compliance with EU guidelines; (2) Meeting Hungarian objectives along with those of the EU (the whole territory of Hungary is considered as "sensitive" area), this being the most expensive solution; (3) Implementation of the Hungarian Master Plan for waste water treatment; (4) A compromise solution, which takes into account different sewerage and sewage treatment in function of the size of the settlement and the interests of the recipient. The strategies were derived on the basis of these alternatives, taking the expectable changes of the GDP and the fraction of the latter to be spent on the development of public utilities into account, along with different schedules for the implementation. The results (tables V. and VI.) gave the following indications (on the price level of 1998): the total investment cost would be in the range of 600-1100 billion HUF and the time of implementation varies in the range of 10-15 years (assuming 5% increase of the GDP and 0.5% of the latter to be spent on the development). The solution, which we prefer, is the compromise solution, - acceptable also in the light of EU expectations - would cost 650 billion HUF and the options of saving are tremendous ones. In terms of water quality this alternative is much more favourable than the one which "mechanically" implements the guidelines of the EU (resulting in a substantial improvement of the quality of rivers of discharge less than 10 m3/s - Figure 3.). Figures 4. and 5. show the relationship between the schedule of investment and the level of services, justifying that the preferred alternative yields favourable results also in this respect. Results of the analysis indicates that in the future there would be a few large plants and a very high number of plants of capacity of less than 25,000 p.e. (population equivalent). In this range it is especially important to develop cost-efficient solutions and the securing of the appropriate technological knowledge of planners and operators. Even the implementation of the cheapest solution (within 10-15 years) would require the three-fold increase of the present annual investments. The total annual cost of waste water collection and treatment would be doubled. Taking the also increasing costs of drinking water supply into consideration, it is feared that the expenditure per unit income would reach a too high level (exceeding 5% of the net personal income), while the present level is already higher than the average of the EU Member States. In the field of public water utilities the desirable tendency points towards integration/re-integration. Implementation of any new structure - in function of qualifying properties - will require the solution of several tasks (especially when one considers the initial foreign attempts on creating a competitive situation). These would inter alia include: the development of a methodology for the unified determination of the fees of the use of properties and the rate of depreciation; the unified legal regulation of pricing; establishment of an independent price-control agency, which is financed by the owners; and the establishment of a quality control organisation. Considerable difficulties in changing the concept in the long term development of infrastructure, having a characteristically large inertia, are expected in this field. The dealing with these matters should be started at research level.

Original languageHungarian
Pages (from-to)625-666
Number of pages42
JournalVizugyi Kozlemenyek
Issue number3-4
Publication statusPublished - Dec 1 2000

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ASJC Scopus subject areas

  • Water Science and Technology

Cite this

Somlyódy, L., Buzás, K., Clement, A., & Licskó, I. (2000). A települési vízgazdálkodás stratégiai kérdései. Vizugyi Kozlemenyek, (3-4), 625-666.